JP4826909B2 - Method for producing hollow molded body - Google Patents

Description

  The present invention relates to a manufacturing method by forging of a hollow molded body mainly used for automobile components.

Conventionally, as a manufacturing method by forging a hollow molded body used for, for example, an automobile component, first, a solid material is cold forged, and both ends are thin-walled portions having a large inner diameter, and positioned between both ends. A hollow molded body is formed in which the intermediate portion is a thick portion having an inner diameter smaller than that of the thin portion, and thereafter, only the thin portion at both ends is hollow drawn by cold forging to reduce the inner diameter at both ends. It is known that the inner diameter of the intermediate portion is made equal to or smaller than the inner diameter of both end portions.
No. 7-53792

  By the way, in the manufacturing method described above, only the thin hollow portions at both ends of the hollow molded body are simply subjected to hollow drawing by cold forging to be formed into a desired shape. It depends on the limit of quantity. For this reason, there is a problem that it is difficult to manufacture a hollow molded body that requires a large facility or that requires a large amount of processing and accuracy.

  Therefore, in the present invention, both ends are opened in a hollow shape and the middle part is left solid, and both ends are drawn. Simultaneously with the drawing, the volume of the solid part in the middle part is set on both the inner and outer sides. It is an object of the present invention to provide a method for producing a hollow molded body that can obtain a large amount of processing and can be molded with high precision by performing plastic working more actively.

  In order to solve the above problems, the present invention is a method for producing a hollow molded body having a small-diameter end portion and a large-diameter intermediate portion, and a through hole is formed in the center portion between the both end portions and the intermediate portion. First, a cylindrical solid material is cold forged to form a primary molded body having the same outer diameter that is solid in the middle and open at both ends. Both ends are drawn while leaving the middle part of the molded body solid, and at the same time as the drawing, the volume of the solid part in the middle part is plastically processed from both the inside and outside, and the middle part is solid and both ends. Forming a hollow secondary molded body having a diameter smaller than the outer diameter of the intermediate portion through the taper portion, and then compressing both ends of the secondary molded body toward the intermediate portion side at the same time The volume of the solid part in the middle part is plastic processed from both the inside and outside, and the middle part is the solid part. While forming a tertiary molded body that becomes a small diameter cylindrical shape that bulges outward and remains large, leaving both ends open, and then punching the solid part of the intermediate part of the tertiary molded body, And a final hollow molded body in which a through hole penetrating the intermediate portion is formed.

  According to the present invention, a solid material is forged to form a primary molded body in which the intermediate portion is solid and both ends are open, and then the both ends while leaving the intermediate portion of the primary molded body solid. The volume of the solid part in the intermediate part is positively plastically processed from both the inside and outside to form the secondary molded body at the same time, so that a large amount of processing can be obtained in the secondary molded body. In addition, it is possible to forge with high accuracy. Similarly, the secondary molded body is compressed by compressing both ends of the secondary molded body toward the intermediate portion side, and at the same time, the solid portion of the intermediate portion is actively plastically processed from both the inner and outer sides so that the intermediate portion is in the middle. While forming the tertiary molded body that bulges outward while leaving the real part and becomes large in diameter and both ends exhibit a small-diameter cylindrical shape, it is possible to obtain a large amount of processing even for the tertiary molded body Can be forged with high precision. After that, by punching the solid part of the intermediate part of the tertiary molded body formed with high accuracy, the final hollow molded body that penetrates both ends and the intermediate part while maintaining the accuracy of the tertiary molded body as it is. Can be finished with high precision.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The figure shows a method for producing a hollow molded body according to the present invention, in which a solid metal round bar is cut into a predetermined length to form a cylindrical solid material A shown in FIG.

  Next, the solid material A is continuously forged with a multistage cold forging machine.

  In the first stage of the forging machine, as shown in FIGS. 2 and 3, the solid material A is upset by the die 10 and the punch 11 to form the formed body B.

  In the second stage of the forging machine, as shown in FIGS. 4 and 5, the die 20 having the forming pin 20a and the punch 21 are provided with the holes C3 and C3 coaxially from both end faces of the formed body B, and the intermediate portion C1 is in the middle. A cylindrical molded body (primary molded body) C having the same outer diameter and having a hollow shape in which both ends C2 and C2 are opened is formed.

  In the third stage of the forging machine, as shown in FIG. 6 and FIG. 7, while the die 30 having the forming pin 30a and the punch 31 having the cylindrical forming portion 31a are left, the solid portion of the intermediate portion C1 in the formed body C is left. Both ends C2 and C2 are drawn, and holes D3 and D3 having inner diameters in which the intermediate part D1 is solid and both ends D2 and D2 are smaller than the outer diameter of the intermediate part D1 through the tapered parts D4 and D4. A hollow molded body (secondary molded body) D having the shape of is formed.

  In the fourth stage of the forging machine, as shown in FIGS. 8 and 9, both ends D2 and D2 of the secondary molded body D are intermediate portions by a die 40 having a forming pin 40a and a punch 41 having a tubular forming portion 41a. At the same time as compressing toward the D1 side, the solid portion of the intermediate portion D1 is compressed, and the intermediate portion D1 is plastically deformed so as to bulge outward and have a large diameter while leaving the solid portion, and the intermediate portion E1. Are hollow and solid, the outer diameters of both ends E2, E2 are smaller than the outer diameter of the intermediate part E1, and the outer diameters of both ends E2, E2 of the intermediate part E1 are hollow. The formed molded body (tertiary molded body) E is formed.

  In the fifth stage (final stage) of the forging machine, as shown in FIGS. 10 and 11, the die 50 having the punching pin 50 a and the cylindrical punch 51 formed of a cylindrical molding portion are used to intermediate the tertiary molded body E. The solid part in the part E1 is punched, and the inner diameter of the intermediate part F1 and the inner diameters of the hollow parts F3, F3 in both end parts F2, F2 are the same, and both the end parts F2, F2 and the intermediate part F1 are A final hollow molded body F in which a through hole F6 penetrating through the inner tapered portions F5 and F5 is formed is formed. The punching waste F7 punched by the punching pin 50a is discharged to the outside through a discharge passage 51a provided on the punch 51 side.

  As described above, the solid material A is forged to form a molded body C in which the intermediate portion C1 is solid and both end portions C2 and C2 are opened, and then the intermediate portion C1 of the molded body C is solid. Since the both ends C2 and C2 are drawn while remaining as they are, the volume of the solid portion in the intermediate portion C1 is positively plastically processed from both the inside and outside to form the formed body D. A large amount of processing can be obtained and forging can be performed with high accuracy. Similarly, both end portions D2 and D2 of the molded body D are compressed toward the intermediate portion D1, and at the same time, the solid portion of the intermediate portion D1 is actively plastically processed from both the inner and outer sides, so that the intermediate portion E1 is in the middle. Since the molded body E is formed to have a large diameter by bulging outward while leaving a real part and both ends E2 and E2 have a small diameter cylindrical shape, a large amount of processing can be obtained for the molded body E as well. Can be forged with high accuracy. After that, by punching the solid part of the intermediate part E1 of the molded body E molded with high accuracy, the both ends F2, F2 and the intermediate part F1 penetrate while maintaining the accuracy of the molded body E as it is. The final hollow molded body F to be finished can be finished with high accuracy.

  FIGS. 12 and 13 show another embodiment. In the fourth stage of the forging machine of the above-described embodiment, a die (not shown) having a forming pin and a cylindrical forming portion are provided. The both ends D2 and D2 of the secondary molded body D described above are compressed toward the intermediate portion D1 by a punch (not shown) having the intermediate portion D1 and the solid portion of the intermediate portion D1 is compressed. When plastic deformation is performed so that 1 has a solid diameter and bulges outward to have a large diameter, the inner surfaces of the tapered portions D4 and D4 are brought into close contact with the wall surface of the inner solid portion of the intermediate portion D1. Thus, it is plastically deformed. As a result, the intermediate portion E′1 as shown in FIG. 12 has a large diameter and a solid diameter, the outer diameters of both end portions E′2 and E′2 are smaller than the outer diameter of the intermediate portion E′1, and the holes A hollow molded body (tertiary molded body) E ′ having E′3 and E′3 is formed.

  Thereafter, in the fifth stage (final stage) of the forging machine, as in the case of the fifth stage of the forging machine of the above-described embodiment, a die (not shown) having a punching pin and a cylindrical molded part A solid portion in the intermediate portion E′1 of the tertiary molded body E ′ is punched by a cylindrical punch (not shown) made of As a result, the inner diameter of the intermediate portion F′1 as shown in FIG. 13 and the inner diameters of the hollow portions F′3 and F′3 at both ends F′2 and F′2 are the same, and both ends F ′. 2, a final hollow molded body F ′ in which a through hole F′6 penetrating the intermediate portion F′1 and the intermediate portion F′1 is formed. Further, the punching waste punched by the punching pin is discharged to the outside through a discharge passage provided on the punch side.

  Also in this case, the same effects as those of the previous embodiment can be obtained.

  The present invention is not limited to the above two embodiments, and for example, the inner diameter of the through hole F4 may be smaller than the inner diameter of the hollow portion at both ends F2, F2, Of course, it can also be used as parts other than automobile parts.

  In the above embodiment, the forging machine having a five-stage forged portion has been described. However, the present invention is not limited to five stages. For example, a solid material A is upset to form a formed body B. In doing so, it goes without saying that the number of stages of the forging machine may be increased as appropriate, for example, by performing an upsetting process in a finer step by adding another upsetting process.

  It is a front view of the solid raw material used with the manufacturing method of this invention. It is a front view of the film container for carrying the mouthwash liquid manufactured by paste.   It is a front view of the molded object in the 1st step of forging by the manufacturing method.   It is explanatory drawing of the forge state in the 1st step | paragraph.   It is a front view of the molded object in the 2nd step of forging by the manufacturing method.   It is explanatory drawing of the forge state in the 2nd step | paragraph.   It is a front view of the molded object in the 3rd step of forging by the manufacturing method.   It is explanatory drawing of the forge state in the 3rd step | paragraph.   It is a front view of the molded object in the 4th step of forging by the manufacturing method.   It is explanatory drawing of the forge state in the 4th step | paragraph.   It is a front view of the molded object in the last stage of forging by the manufacturing method.   It is explanatory drawing of the punching state in the last stage.   It is a front view of the molded object in the 4th step of forging by another embodiment.   It is a front view of the molded object in the last stage by the embodiment.

Explanation of symbols

A Solid material B Molded body B1 Intermediate part B2, B2 Both ends C Molded body (primary molded body)
C1 Intermediate part C2, C2 Both ends D Molded body (secondary molded body)
D1 Intermediate portion D2, D2 Both end portions D4, D4 Tapered portion E Molded body (tertiary molded body)
E1 Intermediate part E2, E2 Both ends F Final hollow molded body F1 Intermediate part F2, F2 Both ends F6 Through hole E 'Molded body (tertiary molded body)
E'1 Intermediate part E'2, E'2 Both ends F 'Final hollow molded body F'1 Intermediate part F'2, F'2 Both ends F'6 Through hole

Claims (1)

  A method of manufacturing a hollow molded body having both small-diameter end portions and large-diameter intermediate portions, and having a through-hole formed in the central portion between the both end portions and the intermediate portion. The material is cold forged to form a primary molded body with the same outer diameter that is solid in the middle and open at both ends, and then the middle of the primary molded body remains solid While drawing, both ends are drawn, and simultaneously with the drawing, the volume of the solid part in the intermediate part is plastically processed from both the inside and outside, so that the intermediate part is solid and both ends are outside the intermediate part via the taper part. Form a hollow secondary molded body with a smaller diameter than the diameter, and then compress both ends of the secondary molded body toward the middle part, and at the same time adjust the volume of the solid part in the middle part Plastic processing from both sides, the middle part bulges outward while leaving a solid part Form a tertiary molded body that has a small diameter cylindrical shape with both ends open, and punch through the solid part of the intermediate part of the tertiary molded body, and through holes that penetrate both ends and the intermediate part are formed. A method for producing a hollow molded body, wherein the final hollow molded body is formed.

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